In addition to the CD, which is generally known as Compact Disc, as digital recording medium for audio signals, further recording media are known which differ from the CD only to an insignificant extent in terms of their structure. When a music aficionado sees a CD, a computer specialist sees a CD-ROM. The designation CD-ROM indicates that what is involved here is a read-only storage medium, or a so-called compact disc read-only memory. While the CD-ROM was regarded primarily as a medium for text and data transmission at its inception, the so-called CD-I standard was then developed in order to extend the possibilities of use for the CD-ROM. In accordance with this standard, texts and data can be supplemented with images, graphics and music. Furthermore, the compact disc with video, known as CD-V, was created for the light music sector, enabling a combination of five to six minutes of video recording including sound and twenty minutes of high-quality digital sound recording on a disc with a diameter of 12 cm.
Despite the different recording formats, CD-like recording formats are involved since the recording media have a corresponding recording principle which consists in digital information storage in a virtually corresponding information track which can fundamentally be read by the same scanning system. However, the differences in the recording format mean that a CD-ROM, CD-I or CD-V, for example, cannot be played back by a CD player in the same way as by a playback device provided specifically for the recording medium. On the other hand, devices for recording formats which differ from the CD recording format are generally set up in such a way that they can also play back an audio CD. Furthermore, however, such devices have additional decoders and controllers for decoding the recording format and controlling the recording medium.